1. Field of the Invention
The present invention is related to a hydraulic drive or clutch assembly. More particularly, the present invention is related to a hydraulic drive or clutch for a stretch conveyor roller. Even more particularly, the present invention is related to a drive or clutch for a conveyor roller for stretching film.
2. Description of the Prior Art
Mechanisms and assemblies for driving conveyor rollers and hydraulic drive assemblies are well known in the art. Exemplary of the prior art are the following U.S. Patents:
U.S. Pat. No. 3,568,821 discloses a power-driven conveyor roller. The roller is the type used in conveyor roller trains. The conveyor roller includes a drum with an enclosed power unit. One end of the drum is journaled in a frame, the other end is journaled on the power unit which projects out from the drum and is fixedly mounted in the frame. The power unit includes a pressure fluid driven sliding vane motor which has two alternative inlets, one of the inlets being used to effect rotation in one direction and the other being used to effect rotation in the opposite direction. Conveniently, the two inlets are provided with variable restrictions, so as to permit some adjustment of the maximum speed by means of the restrictions.
U.S. Pat. No. 3,974,910 discloses a fluid cylinder decelerating means. A piston and cylinder actuator is disclosed embodying means to control the acceleration and deceleration of the piston as it approaches the end of its stroke. Such actuator is also disclosed as an intermittent drive for a machine system in which at least part of the drive connection is provided by a friction drive. The acceleration and deceleration control is arranged to prevent slippage in the drive. The acceleration and deceleration control includes a land positioned on each side of the piston, each formed with a plurality of axially spaced orifices. As the piston approaches one end of its stroke, one land projects through an associated seal which operates to progressively isolate the orifices from the main chamber to control deceleration. Such orifices are progressively uncovered as the piston moves away from its end position, and in one embodiment provides controlled acceleration. The other land functions in a similar manner to control piston acceleration and deceleration at the other end of the piston stroke. One of the lands is provided by a tubular element positioned around the piston rod and proportioned so that it does not significantly change the effective area of the piston as the land comes into or goes out of operation. The lands are proportioned to provide the same deceleration rates at each end of the piston stroke. In a second embodiment, a separate adjustable flow restriction is provided to control acceleration of the piston without materially affecting its deceleration.
U.S. Pat. No. 4,013,166 discloses a hydraulic driven pulley for conveyors whereby a hydraulic motor encased with a pulley drives the pulley and thereby drives a belt conveyor. The motor is encased in a stationary housing and is driven by fluid pumped from an external source through a stationary first shaft into the interior of the pulley. The first shaft and a second stationary shaft are supported by brackets which sustain the weight of the assembly. The pulley revolves on bearings on two shafts. The inner end of the first shaft is supported by one end of the motor housing and the inner end of the second shaft by bearings in a drive flange which is fixed to the motor shaft and to an internal partition of the pulley. The partition is apertured and communicates with a discharge duct in the second shaft so that fluid leaking in the interior of the pulley is discharged.
U.S. Pat. No. 4,265,386 discloses a torsional fluid damper system including methods and apparatus for providing torsional fluid dampening in the kHz region with an inertial mass located in a rotary fluid container, and with a viscous fluid friction boundary layer located between that mass and a circumferential wall of the container. A supply of viscous liquid having a volume equal to the combined volumes of the boundary layer and inertial mass is provided. Both the inertial mass and the boundary layer are formed with that supply of viscous liquid in the fluid container which may then the rotated.
U.S. Pat. No. 4,832,656 discloses a power roll conveyer with an adjustable torque sensitive coupling including a powered conveyor roller having a frictional coupling inside the roller drivingly connecting the roller to a drive shaft extending actually through the roller. The coupling includes a flat spring wrapped around the shaft to form a frictional engagement with a pair of split bushings disposed of the shaft and inside the spring, the opposite end of the spring being connected to the roller in such a manner that the roller is driven by the shaft up to a predetermined load on the roller but the shaft and roller rotate with respect to one another when the load exceeds a predetermined, adjusted level.
U.S. Pat. No. 4,934,123 discloses a method and apparatus for dispensing a web of material including at least one roller adapted to engage the web, a structure for rotationally driving the roller when the web is drawn from the roller at a preselected force, and a planetary gear assembly associated with the driving structure for varying the rate of rotationally driving the roller in response to variation in the force drawing the web from the roller so as to maintain the drawing force at the preselected level.